How resolve llegal in-law for duplex built pre-code in NorCal?

[Kristen W.]

I'm thinking about buying a house that was built in 1914 with an in-law unit downstairs. This house was clearly meant to be a duplex since there are separate entrances and no internal stairs - you can only go from one unit to the other by going outside. However, it was never officially classified as a duplex. I spoke to the Planners office for the county (Contra Costa), and they said it would not be possible for this house to have an ADU because its lot is too small (< 6000 ft). The only way I can use the in-law unit legally as an ADU is if it was classifed as such before 1947. Unfortunately there is no record of this house getting any sort of official classification...perhaps because it was built 40+ years before zoning existed. It seems kind of silly since the house is clearly and obviously a duplex - does anyone have experience with this scenario?

I keep hearing the NorCal counties are relaxing their ADU rules to increase housing stock, but the Planners Office person I spoke to certainly wasn't mentioning that. In case it matters, the house is in an unincorporated area (Crockett).

One other question - I asked the Planning rep if it was OK to have a "roommate" in that space, and apparently that is fine as long as it does not have a kitchen.  Does anyone know what constitutes a kitchen legally?  Is there some sort of mini-kitchenette I could add that would keep things kosher?

I'm guessing I could Airbnb it, but I'd prefer to rent it out as a legal apartment. Any insight or ideas would be appreciated - thanks!